1. Field of the Invention
The present invention relates to a method of using a camshaft miller.
2. Description of the Related Art
In the known art, some types of engine units of, for example, automobiles employ double overhead camshafts (DOHC).
One example of such double overhead camshafts is shown in FIG. 1, in which a pair of cams C.sub.1, C.sub.2 ; C.sub.3, C.sub.4 ; C.sub.5, C.sub.6 ; and C.sub.7, C.sub.8 for suction and discharge, having the same phase, are provided on both sides of respective one of a plurality of journals J.sub.1, J.sub.2, J.sub.3 and J.sub.4 and a ring (fuel cam) C.sub.9 for driving a fuel pump is also mounted on one end.
When the double overhead camshaft of the above structure is manufactured, a workpiece provided with the cams C.sub.1, C.sub.2 ; C.sub.3, C.sub.4 ; C.sub.5, C.sub.6 ; and C.sub.7, C.sub.8 having the same phase on both sides of respective journals J.sub.1, J.sub.2, J.sub.3 and J.sub.4 and with the ring C.sub.9 at its one end portion is worked by means of a camshaft miller. In conventional technology, there are generally employed a method, as shown in FIG. 2, in which the respective cams C.sub.1 -C.sub.8 and C.sub.9 are subsequently worked by using a single cutter a and a method, as shown in FIG. 3, in which the adjacent two cams such as C.sub.1 and C.sub.2 of these cams are simultaneously worked by using a double cutter b.
However, according to the former working method using the single cutter a, many processes are involved and, accordingly, much time is required for working and finishing one workpiece. It is thus difficult to achieve improved productivity using any form of this method.
On the other hand, according to the latter working method using the double cutter b, in a case where the ring C.sub.9 is worked by the double cutter b, one of the cutter elements of the cutter b interferes with the ring C.sub.9 and the working is not executed precisely. In order to prevent this problem, it is necessary to work the ring C.sub.9 by another means, thus being troublesome and hence inconvenient.